The present invention relates to a fluorescent lamp device and, more particularly, a fluorescent lamp device capable of being freely detachably connected to the external socket for an incandescent lamp and used instead of incandescent lamp.
The fluorescent lamp which can be replaced instead of incandescent lamp has become popular these days. The fluorescent lamp of this type has a screw base which can be fitted into the incandescent lamp socket, and when the screw base is connected to the socket, the fluorescent lamp can be used in same manner as the incandescent lamp.
In the conventional fluorescent lamp, a reactance ballast, starter circuit and the like are compactly housed together with a fluorescent tube, in a same space of an envelope which includes a bowl-shaped member and globe. When the fluorescent lamp is kept turned on, temperature in the globe rises undesirably due to heat generated from the ballast and the fluorescent tube, particularly heat radiated from the ballast. It is usually desirable that the fluorescent lamp is designed to achieve maximum fluorescent efficiency when temperature around the lamp is from 20.degree. C. to 25.degree. C. and tube wall temperature is about 40.degree. C. However, temperature in the envelope rises even up to 100.degree. C. because of heat mentioned above. As a result, the intensity of ultraviolet rays of the fluorescent tube and the intensity of visible rays radiated from fluorescent material coated on the inner surface of the tube are remarkably reduced to thereby lower the luminous efficacy of fluorescent lamp.
The bowl shaped member and/or globe in the conventional fluorescent lamp are provided with a plurality of ventilating bores so as to eliminate the above-mentioned drawback. Air outside the lamp comes into the lamp through these ventilating bores and air of high temperature in the lamp flows outside the lamp through these ventilating bores. Temperature rise in the fluorescent tube kept lightening is thus improved a little. However, heat which is radiated from the reactance ballast and which corresponds to most of heat generated can not be expelled enough. In addition, fresh outside air entering into the globe through the ventilating bores is also heated by the reactance ballast. Therefore, temperature in the envelope can not be kept to the above-mentioned one optimum for the fluorescent tube. Particularly when the fluorescent lamp is used the screw base side down, heat radiated from the reactance ballast rises to hit the fluorescent tube directly. Therefore, heat discharge is not enough in the conventional fluorescent lamp and temperature in the lamp can not be lowered to the above-mentioned optimum one (or target one). It can not be expected therefore that the luminous efficacy of fluorescent lamp is enhanced satisfactorily.